Fish with one pectoral (?) fin. Better to let live or put him out of his misery?

Question

I have a Tetra that has only pectoral fin (I think that is the correct fin). We think that another one of the Tetras nibbled off the other. He has been like this for months now. Because of that, he is smaller in size, swims (floats) almost upright, and has a spine that is shaped almost like an elongated 'S' shape. He does eat whenever fed and constantly strives to keep himself afloat. Still, I don't know whether or not it is better to put him out of his misery or to let him keep on living. The animal lover in me wants to let him live as he eats and seems like a definite fighter. Still, I always question whether it is better to take measures and put him out of his misery. Any pros and cons to keeping him alive?

A curved spine is not the result of strenuous swimming due to having only one pec fin? What disease might he have that would cause that?

Answer 1

The curvature could be cause by a number of things - from as benign as a vitamin deficiency (scoliosis), to an internal parasitic infection called camallanus (look for red worms coming out the anus while the fish is at rest, see photo: http://www.gaem.it/pubblico/articoli/malattiepesci/camallanus/camallanus03.jpg ), to fish tuberculosis (which can be transmitted to humans). The vitamin deficiency cause may indicate you need to vary/ improve the diets of your fish or others may get the same problem. The parasite and fish TB are contagious, so they will affect the other fish if either of these is the cause. At the very least, the fish should be isolated from the others to reduce the chance of transmission. If you can determine that the cause is the parasite, the entire tank will need to be treated, because the worms will likely have laid eggs, which will hatch and infect the other fish. At any rate, the spinal curvature will be permanent regardless of the cause or treatment.

If you are able to determine that this is camallanus, see this link for treatment: http://www.inkmkr.com/Fish/CamellanusTreatment.pdf You'll need to go to a farm store or veterinarian to find this treatment - it's typically used for livestock, so you won't see it in pet stores.

If you decide to euthanize your fish, clove oil is the most humane method as it aenesthetizes the fish. From there, you can overdose the anesthesia, or freeze it: http://www.wisegeek.com/what-is-the-most-humane-way-to-euthanize-a-fish.htm

Answer 2

You don't state what TYPE of tetra he is. The thing that is alarming me is the S shaped spine: If he is a neon tetra please read below and euthanize. If not, the fish could have scoliosis (curvature of the spine) making it an easy target. In that case, I would just watch carefully. If you have another tank to put him in, I'd treat with maracin to see if the fin can grow back.
Unfortunately, neon tetras are occasionally afflicted by the so-called "Neon Tetra Disease" (NTD) or Pleistophora which is usually fatal to the fish, and currently without a cure. This sporozoan disease is caused by Pleistophora hyphessobryconis.

The disease cycle begins when microsporidian parasite spores enter the fish after it consumes infected material such as the bodies of a dead fish, or live food such as tubifex, which may serve as intermediate hosts. The disease is most likely to be passed on from newly acquired fish, which have not been quarantined.

Symptoms: restlessness

1. Fish begins to lose coloration.
2. As cysts develop, the body may become lumpy.
3. Fish has difficulty swimming.
4. In advanced cases the spine may become curved.
5. Secondary infections such as fin rot and bloating.

Note that there is a so-called "false neon disease", which is bacterial, and shows very similar symptoms. It is impossible for the home aquarist to determine for certain the difference between NTD and false NTD on the basis of visible symptoms alone, without laboratory backup. This disease has also been confused with Columnaris (mouth rot, mouth fungus, 'flex').

To date, there is no known cure: the only 'treatment' is the immediate removal of diseased fish to preserve the remaining fish. The use of a diatom filter, which can reduce the number of free parasites in the water, may help.

Answer 3

I would point out that a missing fin wouldn't cause the curved spine. That is the sign of a terminal disease and I would suggest you euthanize the fish to protect the other fish in the tank as it could spread when your sick fish dies.

MM

Answer 4

Breeders that end up with fish with curved spines always cull them. It is up to you what you do with it. Personally, I would leave it alone. If you decide to put him down, put him in a plastic bag with a bit of water and freeze him. He will die painlessly.

Answer 5

ive never been able to kill my fish. if i did i woundnt be able to buy that type of fish because of the sadness. you should put it in a different tank. no dont freeze him what about the moments of coldnnes. there is no painless death its either hurting it a lot at once orlet it live with the hurt and live longer. i think it would want to live longer. i dont see people killing them selfs. only if they had a really had past child abuse and stuff

Answer 6

if you do decide to cull him, since he is a tropical fish, take a cup of very cold (that had a glaze of ice on top) and simply drop him in. he will die instantly of shock.
it doesn't sound like he is enjoying life. just remember that animals live in the now, and all he knows now is suffering.